Hypodermic needle



Oct. 8, 1940. J. c. sMrrH HYPODERMIC NEEDLE Filed May 12, 1958 2Sheets-Sheet l INVENTOR. Jesse Conrad/Snail@ Q Q o o Q Q QOOOQOOOOOOOOOQw.@wwwwwwwwwwwwv ATTORNEYS Oct. 8, 1940. J. c. SMITH HYPoDERMIc NEEDLE 2Sheets-Sheet 2 Filed May l2 1958 INVENTOR. @sse @bn/'ad /S'm Z SIBY rUr/wv. ATTORNEYS. l

Patented Oct. 8, 1940 UNITED STATES PTENT oFFicE HYPODERMIO NEEDLE Jesseconrad smith, Merrick, N. y., assignmto MacGregor Instrument Company,Needham, Mass., a corporation of Massachusetts application May iz, 193s,sei-m No. 207,524 v claims. (ci. 12s-221) This invention relates tohypodermic needles and particularly to one of novel construction andincreased eillciency and economy, this application being a re-ling inpart of my previous ap- 5 plicatlon Serial No. 24,835, led June 4, 1935.

According to my inventions it can be produced at low manufacturing costso as to be available to the professions and their service to the publicwithout added charge and with greater safety in operative use.

The usual hypodermic needle, developed by long years of experience foruse with syringes for giving various kinds of injections subcutaneously,had come to a rather standard type or types, generally accepted bydoctors, dentists and `nurses for use on their patients. It generallyconsisted of a hub or base for engagement with the usual glass Luersyringe tip, and a so-called cannula which was really the needle portionof the instrument.

By highly developed processes these cannulae were eventually availableas small seamless steel tubes of hollow wire-like formation. They werecut to length, tempered and carefully ground at one end to an angularincising point generally 'in a plane at an acute angle to thelongitudinal axis of the hollow wire of the cannula stock.

The cannula of the hypodermic was usually set in a metal hub which wasusually milled and turned out of contoured stock-and axially drilled andreamed for accurate'frlctionalv reception of the syringe tip. For theLuer type of syringe the hubs were formed with a conic recess to makecareful frictional contact on the glass tip of the Luer or like syringeon which it was to be used as a combined instrument in the hand of theoperator.

Unfortunately, in spite of high skill and the greatest of care, thecannulae of these hypo- 40 dermic needles would break while being thrustthrough the skin or underlying tissues of the patient. This was due tothe fact that in most cases the steel needles or cannulae mounted in anindependent hub tended to break at the joint line when the needle orcannula is set in the hub in a joint which formed a sharp fulcrum line.Such were often crystallized during soldering or by blows upon it whenswaged in place.

Such breakages were nerve wracking to both operator and patient. Oftenthe results were painful and so dangerous that various efforts were evenmade to provide needles that would break far enough back from the pointto leave an external stub which couldbe located and surgically engagedfor extraction.

Furthermore, needles which have rough surfaces or which carry particlesor substances which adhere during the process of formation of theneedles. and which are not removed, tend to carry infectious matterunder the skin of the 5 patient, and such adhering particles orsubstances tend to come loose and be injected in the patients bodytissues or circulatory system.

Moreover, irregularities in the interior surfaces or materials adheringto such surfaces, tend lo to obstruct the passage of injected fluid, andset up a point for rust formation or other co1'- rosive action whichwill weaken the needle, often to the point of breakage. `The removal ofsuch irregularities or accumulated substancesl from the 15 outer surfacemay be readily accomplished but it is impossible as a practical matterto remove them from the inner surface after the fabrication of theneedle is complete.

When an annealing process is utilized in the l0 formation of steelneedles, scale, particularly in the form of oxides, tends to be formedand while such scale can be readily removed from the outer surface ofthe needle, that remaining in its bore is highly diilicult to eliminate.Needles produced 25 by Wide-drawing processes moreover, tend to gatherparticles of'carbon from the graphite lubricant employed, and to retainthese particles. The usual steel needles tend to rust unless verycarefullyhandled, and this tendency is often 3G accentuated by thesterilizing materials used.

It is of great importance that the bore of the needle be kept clear ofthe accumulation of any solids suspended in the injection fluid, and tothis end it is desirable that a cleaning wire may 35 be readily insertedthroughthe hub of the needle and passed along its length by continuouspassage without encountering obstructions, and that the needle may beeasily sterilized as to its interior. Accordingly my invention providesfor 40 the avoidance of shoulders, pockets, or yother longitudinalobstructions Y which will tend to gather solid particles or oppose themovement of a cleaning wire or fluids.

Another important desideratum is the provision of a needle having a hubmember which is sufliciently resilient frictionally to t over thenozzles of hypodermic syringes and the like even though the contours ofthese nozzles may vary slightly. 50

My concept, based on a careful study of the situation, was that of ahypodermic needle which would have no weakest place and so would standup under adverse operative conditions and do so without embarrassingdeparture from acc vpteci 55 standards and the practice land habitsformed thereon.

Needles according to my inventions have several advantages over thosemade with the old shaped hub with a swaged; soldered or brazed-incannula. My needles, even under the strains imposedby the leverage ofthe syringe which the operator uses as a general handle, and evn withpatients having tough resistant tissue to be penetrated, stand up inoperative use because they transmit and absorb those stresses andstrains which break the present type of hypodermic needle.

Aside from performance, the structures of my needles show consistentlyrelated factors which are self-explanatory to the professions and tothose skilled in the manufacturing art.

For the purposes of ready comprehension of the novel construction of myneedle and its advantages, it may be helpful at the outset to explainits novel basis of actual fabrication because of the long pre-conceivedconvictions of the trade to the contrary.

By reason of Patent Office classification the method and apparatus formaking such needles is made the subject matter of a separate appli--cation for patent, so that it is not claimed herein, but only suggestedas explanatory of the accomplished fact which was supposed to beimpossible.

Such a needle may be formed in one piece from a single blank of sheetmetal. The provision for a one piece construction is highlyadvantageous. The metal used is desirably stainless steel, but in thebroader aspects of the invention may be any metal or alloy whichpossesses, or which by treatment such as hardening and tempering, may bemade to possess the desired hardness and other qualities, and which hasenough ductility to permit it to be pressed and swaged in accordancewith the invention. The term stainless steel is usedto define steelhaving a relatively high resistance to corrosion. A desirable stainlesssteel for use is, for example, commercial Carpenters No. 2, containingabout 15% chromium and .3% carbon; alloys of berryllium with nickel (forexample containing about 1.6% beryllium), alloys possessing propertieswhich make them well adapted for use in accordance with the invention.Other beryllium alloys may be utilized. Nickel and various other hardmetals and alloys which can be worked sufficiently for the purposes ofthe invention may be used. Cold rolled steel may be utilized where theneedle is to be carefully protected or where for other reasons relativetendencies toward rusting are not an important draw back.

In accordance with my concept a. disc-like piece of sheet metal may bepressed into an elongated cup-like member. When the-cup-like member hasbeen suiiiciently elongated and suitably shaped, as by die-pressing, theend which corresponds to the center of the die may, in carrying outtheinvention, be elongated into needle form by a succession of swagingoperations, each i' 'involving a series of intermittent pounding orsqueezing actions which will be designated herein as blows, delivered atdifferent points on the work schematically illustrated in an explanatoryfigure included in the drawings.

As illustrative of my inventions I have shown in the accompanyingdrawings novel needle types with indicated basis of fabrication. Inthese drawings:

Fig. 1 is a side elevation of a needle in accordance with my invention.

Fig. 2 is a central longitudinal section through the needle unit shownin Fig. 1.

Fig. 3 shows a modified form in elevation illustrating mergingcontinuity of integral hub and cannula walls in my needle.

Fig. 4 shows a knurled cylindric form.

Fig. 5 indicates another type having more taper than that of Fig. 4,with a hub portion also cylindric and with parallel axial knurlings.

Fig. 6 is .an end view of the needle shown in Fig. 1 viewed from theopen hub end.

Fig. 7 is a view partly sectioned indicative of the relation of one ofmy needles to a syringe tip on which lt is mounted and to an indicatedarea of application as of patient tissue.

Fig, 8 shows a section through its taper as at 8 8, Fig. 1. l

Fig. 9 is a similar section on the line 9 0, of Fig. 3, and

Fig. 10 shows an explanatory group of figures indicative of theprogressive steps by which such a hypodermic structure may be developedto attain the continuous wall figure between integral hub and cannulaaccording to-my concept of such a needle.

Embodiments of the invention are shown in the form of a hypodermicinjection needle in Figs. 1, 2 and 3. As will be seen, the needlecomprises a hub portion 9 and a cannula point portion l0 connected by atapering portion I, which portions are formed of a single continuouswall of sheet metal. The needle so formed is without seams or breakagelines and has a thin practically uniform wall throughout its extent.

Such a needle exterior iiares in smooth longitudinal curves throughoutthe part where the hub portionv and the cannula portion merge so thatthere are no sharp fulcrum lines which would result in breakage. As willbe apparent from consideration of Figs. 1 to 5, inclusive, the portion 8connecting the hub 9 and cannula l0 is formed as a. concaved conicfigure which merges with the straight cylindrical wall of the cannula I0and preferably also with the h'ub 8,

.in a curve of a circle tangential to the walls of the cannula and hub.These will also be noted by comparisons of such sections as Figs. 8` and9. The inner surface of the needle is likewise continuously smoothlycurved longitudinally so as to be without shoulders or pockets whichwould interfere with easy washing or would obstruct the movement of acleaning wire.

The point portion terminates in a sharp point II which may be of usualangular form ground and honed to incising sharpness. The inner surfaceof the hub has a slight taper to t about the nozzle`|2 of a hypodermicsyringe I3 (Fig. 7). The bore of the point portion of the needle may be,say .005 in diameter, and the wall of this portion may be about .005"thick. 'I'he wall of the hub portion may have a thickness in theneighborhood of .020", if desired. Due to the uniform, thin contour ofthe upper portion of the hub, the hub has suincient elasticity to tsnugly over a syringe nozzle having a periphery which does not exactlyconform to the interior wall surface of its hub. Such needles aresubstantially free from breakage lines of any sort, and in accordancewith my inventions the cannula portion can be semi-polished both insideand out and substantially free from surface irregularities and fromadhering particles or substances which would roughen the surface or comeloose in use.

For simple forms the needles are'preferably y finger hold in operation.

For the purposes of further visualizing the novel structure of myneedles I have indicated in Fig. 10 certain significant steps in amethod by which the invention may be commercially available and wherebya thin-walled tubular article like a needle may be produced. Asexemplied such a method is adapted for the production vof needles suchas are shown in Figs. l,l

2 and 3. Such a method involves turning up the edges of a disc-likepiece of sheet metal to form a cup-like member. For example, a disc ofstainless steel (or other suitable metal) as indicated at A, may bepressed into the blank indicated at B. For example, aldisc about thediameter of a quarter of a dollar, and about .017" in thickness may beutilized for the production of a hypodermic injection needle of usualcommercial sizes. If desired, a disc-like piece may in a singleoperation be cut from a large sheet of metal and shaped to assume theconformation shown at B. By successive operations this may be pressedinto successively elongated shapes which may include those shapes shownat C, D and E.

The shaping of the member may be conducted in any desired manner, forinstance, in a punch press, wherein a suitably sized plunger serves topress the cup-like member through suitably proportioned and positioneddies. Desirably, when the cup-like member has been suitably elongated,its closed end is still furtherl narrowed, as indicated at F. Inaccordance with the invention, a portion of the member adjacent to itsrim may be given an outwardly tapered conformation to provide a hubwhich will t firmly over the tapered nozzle of a hypodermic syringe. Thehub walls may be readily thinned down during certain of the pressingoperations in cases where a thick initial sheet was used or where theearly pressing operations tendedto thicken the walls. I find in practicethat a desirable wall thickness is from .015" to .020", but even whenthe thickness is considerably greater, the hub will have sufiicientflexibility to conform easily to tapered syringe nozzles of slightlyvarying contours. As likewise indicated at F, a bead may also be formedat the rim of the member. 'Ihe provision of the bead at this stage ofthe operation facilitates the holding of th e needle during subsequentope erations.

As hypodermic needles as herein described may be of any standard design,I claim them as novel articles of that class.

What I therefore claim and desire to secure by Letters Patent is:

v1. A seamless, one-piece hypodermic needle formed from a blank of sheetmaterial and cornprising a hollow hub portion of relatively largediameter for engagement with a syringe, a thinwalled cylindrical cannulaportion having a sharpened penetrating end, and a hollow taperingportion connecting said hub and cannula portions, the outer surface ofsaid connecting portion having a gradual concavely-curved mergence withthe outer face of said cannula portion, and1 a gradual convexly-curvedmergence with the outer face of said'hub portion, and the inner face ofsaid connectingportion having a gradual convexly-curved kmergence withthe'inner face of said cannula portion and a gradual concavely-curvedmergence with the inner face of said hub portion, whereby the innersurfaces of the connecting portion, hub and cannula are continuouslysmooth for the free ow of' uid therethrough and whereby the bendingstrains applied to the cannula'are distributed over a substantial lengthof the needle.

2. A seamless, one-piece hypodermic needle formed from a blank of sheetmaterial and comprising a hollow hub portion of relatively largediameter for engagement with a syringe, a thinwalled cylindrical cannulaportion having a sharpened penetrating end and a hollow tapering portionconnecting said hub and cannula portions, the outer face of saidconnecting portion having a gradual concavely-curved mergence with theouter face of said cannula portion, and the inner face of saidconnecting portion having a gradual convexly-curved mergence with theinner face of said cannula portion, whereby the inner surfaces of theconnecting portion and cannula are free from seams and crevices whereinbacteria may collect and continuously smooth .to facilitate cleansingand sterilization and for the free flow of fluid therethrough andwhereby the bending strains applied to the cannula are distributed oversaid connecting portion.

3. A seamless, one-piece hypodermic needle formed from a blank of sheetmetal by successive drawing and swagingoperations to produce arelatively `thin resilient wall of substantially uniform metalliccomposition and homogeneity throughout and defining a hollow hub'portionof relatively large diameter for engagement with a syringe, acylindrical cannula portionhaving a sharpened penetrating end, and ahollow tapering portion! connecting and merging with said hub andcannula portions. said connecting portion being formedy substantially asa concave conic figure and merging with the cannula in a curvetangential to the straight cylindrical wall of the cannula, the wail ofsaid merging hub and connecting portions being of substantially the samethickness and of thel same configuration internally and externally, theinner merging surfaces of said cannula and connecting portion being freefrom seams and crevices-wherein bacteria may collect and continuouslysmooth for the free flow of fluid therealong, and said.

conic portion being of substantial length and transmitting and absorbingthe bending strains applied to the cannula in use.

4. A seamless, one-piece hypodermic needle formed from a blank of sheetmetal by succes-- sive drawing and swaging operations to produce arelatively thin resilient wall of substantially uniform metallic.composition and homogeneity throughout and defining a hub portion ofrelatively large diameter -and sumcient flexibility for engagement withsyringe tips of slightly varying contours, a cylindrical cannula portionhaving a sharpened' penetrating end, and a tapering portion/connectingand merging with said hub and cannula portions, said connecting portionbeing formed substantially as a .relatively long cone, the apex ofthecone gradually merging into the straight cylindrical wall of thecannula, the wallof' said merging hub and connecting portions beingv ofsubstantially the same thickness andof the same configurationvinternally and externally, said connecting portion absorbing thebending strains`applied to said cannula portion in use, the innermerging surfaces of said cannula. and connecting portions being freefrom seams and crevices wherein bacteria may collect and continuouslysmooth for the free iiow of fluid therealong and to facilitate cleansingand sterilization.

5. A seamless, one-piece hypodermic needle formed from a blank of sheetmetal by successive drawing and swaging operations to produce arelatively thin resilient wall of substantially uniform metalliccomposition and homogeneity throughout and dening a hub portion ofrelatively large diameter and sui'ilclent flexibility for engagementwith syringe tips o1' slightly varying contours, a cylindrical cannulaportion having a sharpened penetrating end, and a tapering portionconnecting and merging with said hub and cannula portions. saidconnecting portion absorbing and transmitting the bending strainsapplied to the cannula during use and presenting a continuously smoothinner surface for the free ow of uid therethrough and to facilitatecleansing and sterilization, the inner merging surfaces of said cannulaand connecting portions being free from seams and crevices whereinbacteria. may collect.

JESSE CONRAD SMITH.

